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    Please use this identifier to cite or link to this item: http://tkuir.lib.tku.edu.tw:8080/dspace/handle/987654321/34851

    Title: 通入氣泡對掃流微過濾中粒子附著與過濾通量之影響
    Other Titles: Effects of air-sparging on particle deposition and filtration flux in cross-flow microfiltration
    Authors: 吳効峰;Wu, Shiau-feng
    Contributors: 淡江大學化學工程與材料工程學系碩士班
    黃國楨;Hwang, Kuo-jen
    Keywords: 掃流微過濾;通氣;多相流;粒徑分佈;cross-flow microfiltration;air-sparging;multiple phase flow;wide size distribution range
    Date: 2008
    Issue Date: 2010-01-11 05:41:18 (UTC+8)
    Abstract: 本研究在掃流微過濾中通入氣體,並改變液體速度、氣體流量以及過濾壓差,討論這些操作條件對過濾通量、粒子附著機率、濾餅性質以及濾面上剪切力的影響。實驗中以平均孔徑為0.1 μm的醋酸纖維膜過濾具粒徑分佈的聚甲基丙烯酸甲酯。隨著氣體流量的提昇會出現不同流態,在氣泡流動的範圍下,作用於膜面上的剪切力能有效抑制濾餅生成,並且可以提高濾速,但隨著流態由氣泡流動轉變為團狀流動,剪切力迅速增加的結果,會造成粒徑5 μm以上的粒子之附著大幅減少,在小粒子填補空隙後導致孔隙度下降,與流體對濾餅壓縮的雙重作用下,使過濾比阻出現明顯的增加,濾速反而比未通氣的數值低。配合力分析的結果可以發現,氣體對粒子造成的作用力在過濾中扮演極重要的角色。本研究所提出基於力分析的粒子附著機構,可以用來預測濾餅中之粒徑分佈,粒子之附著機率與濾餅性質。
    The effects of filtration flux、adhesion probability、cake properties and shear stress by changing liquid velocities、gas velocities and filtration pressures for air-sparging cross-flow microfiltration are studied. A filter membrane made of mixed cellulose ester with a mean pore size of 0.1 μm is used for filtering wide size distribution range particles, PMMA-7G. The flow behavior will change when gas velocity increases. Shear stress can restrain cake mass availability and improve filtration rates under bubble flow, but specific filtration resistance will increase clearly and filtration rates worse than no sparging filtration under slug flow。Because of shear stress increase rapidly。A great of particle decrease above 5μm. Smaller particle move in the void and the porosity become reduce. On the other hand, the cake layer compressed when fluid went past, so the specific filtration resistance increases glaringly. Communion with force analysis, we can find air-sparging force plays important role in filtration process, and we can use simulation analysis to forecast the tendency for particle distribution and adhesion property.
    Appears in Collections:[Graduate Institute & Department of Chemical and Materials Engineering] Thesis

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